a. Field of the Invention
This invention relates generally to window cover systems, to window cover systems using various cover materials such as pleated or non-pleated fabrics or slats or blinds, and to vertically and horizontally oriented cover systems, that is, those in which the pleats or blinds or slats are oriented vertically or horizontally.
The term "window cover" is used here for convenience, but with the understanding that my invention can be used to cover other areas or openings, such as doorways. Also, for convenience frequent reference is made to pleated fabric window cover systems, but this reference is exemplary and not limiting, for as indicated above the invention is applicable to various materials, including non-pleated fabrics and blinds. As shown in FIG. 2, the terms "longitudinal width" (or simply "width") and "height" of a window cover refer to the dimensions "w" and "h", respectively.
b. Current State of the Relevant Art
Over the past several years, pleated shade systems have become a popular form of window treatment. One version of a pleated shade system available from Verosol USA, Inc. of Pittsburgh, Pa., under the trademark RIDEAU, utilizes a prepleated fabric with strong, permanently set pleats which pack very tightly. The Verosol fabric pleats are single pleats. Another version of prepleated fabric is a dual pleated "hollow" fabric recently introduced by the Window Fashion Division of Hunter Douglas, Inc. of Broomfield, Colo., under the trademark DUETTE. Graber, Inc. markets a CRYSTAL PLEAT brand, dual hollow pleated fabric window cover. A seamed pleated fabric cover is available from Verosol, USA, Inc. under the trademark FINALE.
Several of these pleated fabrics work very well in pleated shade systems because the pleats run horizontally and the regularity of the pleats is controlled by the weight of a board or other length of rigid material fastened to the bottom edge of the area of pleated fabric.
A major problem associated with attempting to use the prepleated material in vertical orientations is the difficulty in providing uniform hanging of the pleats. Because of the strongly set pleats, the material tends to behave like a tension spring. The pleats have a spring inherent bias toward the packed-together or closed state of the fabric. When used in a vertical drape, this spring force makes the material hang with uneven draping when the drape is closed (i.e. the open state of the pleated fabric) because the bottom portion of the material which is not mechanically constrained tends to draw together. Thus the pleats do not hang straight and the appearance is unacceptable.
An additional problem occurs when the drape is being traversed open (closed or packed state of the fabric) after being left in a closed position for a length of time. The pleats of the drape do not always pack consistently and tend to distort out of the plane of traverse of the drape. This makes it difficult to obtain a uniform pleating of the drape as it closes and requires hand adjustment of the individual pleats of the fabric.
Vertical blind systems are also popular window covers and share some of the same problems. It would be preferable to use the same string ladder spacing and confining system in a vertical blind that is used in horizontal blind. However, if a string ladder is used, the weight of the ladder itself tends to distort the shape of the overall blind, especially at the edges where the bottom portions of the edge slats tend to be pulled inward. Furthermore, when the vertical blind is traversed from a closed to an open position, the slats tend to distort out of the plane of traverse due to unevenness in the folding of the string ladder material between slats.
My two recent patents, U.S. Pat. No. 4,858,668, issued Aug. 22, 1989, entitled VERTICAL WINDOW COVERING SYSTEMS, and its continuation-in-part, U.S. Pat. No. 4,915,153, issued Apr. 10, 1990, also entitled VERTICAL WINDOW COVERING SYSTEMS, disclose vertical cover support systems which are especially adapted to overcome the above problems associated with vertically mounted draperies and blinds. The '668 and '153 patents are incorporated by reference. Referring to FIGS. 1 and 55, in one preferred embodiment, the vertical cover support systems disclosed in these patents include an elongate mounting platform 2, which is adapted for easy traverse along the system track 1, and means 4 which extends through a slot in the bottom of the traverse track for mounting a vertical drapery edge stabilizer 3. The end of the window cover 5 is attached to the rigid edge stabilizer member 3, which in turn is rigidly mounted to the platform 2 by member 4 and is held by the platform in a rigid vertical orientation to thereby maintain the end of the drapery 5 or other cover in a precise vertical orientation. A cord tensioning arrangement 6 maintains the cover in the vertical plane of the system (the vertical plane extending downward from the traverse track 1). Preferably the platform 2 is elongate along the direction of the traverse track 1 and includes spaced wheels 7--7 which are captured between top and bottom rails of the track, thereby providing the combination of a stable horizontal mounting platform for the vertical edge stabilizer 3 and easy, finger-tip traversal along the track. Other features may include a torque release arrangement (not shown) for releasably mounting the edge stabilizer to the platform 2 and allowing the edge stabilizer to pivot when a predetermined sideways force is applied, to prevent damage to the system.
Like all thing conceived by humans, the vertical cover support systems disclosed in my above patents are not perfect. Specifically, although the systems are quite effective, it is desirable to have a system of even greater simplicity and lighter weight which provides the stability, ease of traverse and other improved characteristics described in my above-described patents.
In addition to the vertical string ladder venetian blind systems mentioned above, there are available non-ladder, vertical blind cover systems comprising vertical slats which typically are suspended from a top traverse track (the slats are free at the bottom). These slats traverse open and closed along the longitudinal width of the track and the individual slats pivot about vertical mounting axes so that when the blind array is partially or wholly closed across the window opening, the slats can be pivoted open and closed in unison, similar to the horizontal opening and closing of horizontal venetian blinds.
The above vertical slat blind systems are not stable and move undesirably, for example, when subjected to air currents associated with heating or air conditioning outlets or wind. The movement includes longitudinal swaying (along their width, w, FIG. 2), distortion, which is in and out movement transverse to the plane of the cover (the plane of FIG. 2), and flutter, which is vibration about the vertical slat axis. Quite obviously, such movements detract from the proper function and enjoyment of the blinds, as well as their durability. For example, vibration can cause rapid deterioration of the blind mounting apparatus, damage to adjacent walls, etc.